Dredge



May9, 1944- w. w. JOHNSON 2,348,389

DREDGE Filed 0st. 13, 1941 lNVENTOR WAL TE 2 W JOHNEON BY m ' H 5 ATTORNEY Patented May 9, 1944 UNITED TA ES PA NT FFIC r QQDREDGE i WalterWdohnson, Berkeley, Calif. v A a 2 g A imation number, '13, 1941, Serial No. 414,715 r g l 4 Claims. (Cl. 37,-71)

- My invention relates to dredges' such .as used for .gOld mining.

It is among the objects of my invention to provide a dredge having improved means for operat, ing a bucket adapted for scooping up material.

Another object is to provide improved means for dumpingv the bucket.

The invention possesses other objects andfeatures of advantage, some of which, with the foregoing; will be set forth in the following description of my invention; It is to be understood that Ido not limit myself to this disclosure of species of my invention, as I may adopt variant embodiments thereof within the scope of the claims.

Referring to the drawing:

The figure of the drawing is a side elevational View showing portions of a dredge embodying the improvements of my invention. 1-

In terms of broad inclusion, the dredge of my invention comprises a movable arm, a bucket movably mounted on the arm, means for, moving the arm between filling and dumping positions,

means for changing the length of the arm, and,

mean for dumping the bucket. The dredger han m ism n edon a buoyant body; and the bucket arm is preferably pivotally mounted for movement from filling osition under the body to a dumping position above the body.

In greater detail, and referring to the drawing, my improved dredge comprises a buoyant body 2 having a recess or well atthe bow in which a bucket arm may work, the rear end of the recess being indicated by dotted line 4. Arm 3 is pivotally mounted on the superstructure of the dredge for movement from filling position under body 2 to dumping position above the body; the retracted position being shown by solid lines and several others including the dumping position being indicated by dot and dash lines.

Body 2 of the dredge is suitably haped and proportioned with sufficient buoyancy to fioat on a pond 6, from the bottom and along the bank I of which, material containing values is being recovered. The superstructure of the dredge comprises two main sid frames 8, one leg only of which is shown in the side elevational view, rising from the deck of body 2 and terminating in a header beam 9 at the peak. Only such parts of the superstructure as provide support for the mechanisms being described are illustrated, it being understood that other struts may be provided to give the necessary bracing.

Means are provided for pivotally mounting the bucket arm; and means associated with the pivot the arm; For this purpose a hollow casting ldis freely journaled on a shaft H mounted on 'a beam I2 of the superstructure. Arm 3 slides in this casting; and carries a rack l3 meshedwith' a pinion M; the latter being rotated by shaft I through a suitable drive connection I 5. Shaft II i driven in either direction to lengthen or. shorten the bucket arm by reversing mechanism:- included in themotorfll connected to thecshaft by suitable reduction gearing. By thisarranga; ment the bucket arm may be lowered to the desired depth relative to the bottom of the pond.

. Ascoopbucket i6 is pivotallymounted to'the end of arm 3 on a cross shaft or pin 1H there bee: ing preferably two side members on arm3, one disposed on each side of the bucket andeach having a rack-and-pinion connection to the drive i5. The bucket has a scooping lip atone end, and. is held in scooping position by arms l8 preferably cast integral withthebucket- Each arm is has. a stop l9 adapted to bear against a side member mounting is provided for changing the length of This is preferably accomplished by a pair of pull;

lines or cables 2|, only one of which is shown in the side view. Each line is fastened to a bucket pin I 1, and is adapted to pass over a guide sheave 22 journaled at the bow of the body 2, for the purpose of changing the direction of pull of the line when the bucket is under the body. From sheave 22 the line passes over a sheave 23 journaled on a strut 24 at the peak of the superstructure, and thence passes to a drum 26 supported by a beam 21. Since there are two lines, there are two of these drums, preferably mounted on a. common shaft 28 and rotated through a reduction gearing 29, driven and controlled by any suitable means, such as a motor with clutch and brake mechanism interposed between the motor and gearing in accordance with well known practice.

In operating the dredge the operator lowers the bucket and adjusts the length of arm 3 to the proper depth. Tension is then applied to lines 2| to swing the bucket forwardly in a scooping stroke, the length of arm 3 being controlled to regulate the depth of cut and to clear sheave 22 as the bucket emerges. After emerging with a load of material the line leaves sheave 22 and the length of arm 3 is left unchanged so that it swings up on a constant radius to the dumping position. I

Means are provided for dumping the bucket. This is accomplished by a fixed cam 3| for engaging a follower roller 32 on arm N3 of the bucket as bucket arm 3 moves into the dumping position. This cam is so shaped as to rotate the bucket forwardly about the axis of pin l1 until the material is discharged over the bottom lip at the rear of the bucket. A stop 33 on the side of the bucket engages a side member of arm 3 to limit turning movement of the bucket in the dumping position.

Material discharged from the bucket is directed into a rotating screen 34 by an inclined chute 36. Should a boulder be picked up by the bucket, the operator lowers a shelf or grating 31 to a position under the bucket for deflecting the boulder down an overhead chute 38. Shelf 31 is pivoted to a brace 39 of the superstructure; and is raised and lowered by a link 41 and crank 42 fixed on the shaft 43 actuated by a suitable air cylinder, not shown.

Following the dumping of the bucket, the arm 3 is lowered by letting out lines 2| to move the bucket back into filling position. Sheaves 22 are arranged below sheaves 23 so that lines Zl automatically fall back into engagement with the lower sheaves as the arm is lowered. The flanges of sheaves 22 preferably flare out at a widespread angle to insure reengagement of the lines, and to give clearance for the terminal connections at the points where the lines are fastened to arms 3.

Other elements of the dredge, such as the recovery tables for the values and conveyor for the tailings are not illustrated because they form no part of my invention.

I claim:

1. A dredge comprising 7 a buoyant body, a bucket, an arm on which the bucket is pivotally mounted, said a'rm arranged on the body for carrying the bucket into filling position under the body and to dumping position above the body, cam means for turning the bucket relative to the arm to discharge material therefrom in the dumping position, anda stop upon the bucket for engaging the arm to limit turning movement of the bucket in the dumping direction.

2. A dredge comprising a buoyant body, a bucket, an arm on which the bucket is pivotally mounted, said arm arranged on the body for carrying the bucket to filling position under the body and to dumping position above the body, means carried by the bucket and normally engaging the arm for holding the bucket against pivotal movement during the filling operation, and a fixed cam on the body for turning the bucket relative to the arm to discharge material therefrom upon movement of said arm into the dumping position.

3. A dredge comprising a buoyant body, a movable dredge arm upon the body, a bucket pivoted upon the arm, means for moving the arm to carry the bucket between a filling position below the body and a dumping position above the body, a bracing arm upon the back of the bucket, a stop upon the arm normally engaging the arm for holding the bucket in scooping position, a fixed cam adjacent the dumping position of the bucket, means upon the bracing arm for engaging the cam to turn the bucket relative to the dredge arm to a dumping position, and a stop upon the bucket for engaging the dredge arm to limit the turning movement of the bucket.

4. A dredge comprising a buoyant body having a superstructure, a dredge arm pivoted upon the superstructure and comprising a pair of spaced parallel members, means for adjusting the effective length of the dredge arm, a bucket pivotallymounted between the outer ends of the side members of the dredge arm, bracing arms upon the back of the bucket, stops upon the bracing arms engaging the backs of the side members for normally holding the bucket in scooping position, means for moving the bucket between a filling position below the body and a dumping position above the body, and means for imparting a limited turning movement to the bucket relative to the dredge arm as it is moved into its dumping position.

WALTER W. JOHNSON. 

